Electromagnetic piano-player.



N0- 8 79,879. PATENTED FEB. 25, 1908. W. B. KRAFT.

ELECTROMAGNETIC PIANO PLAYER.

APPLICATION FILED JUNE 19.1906

2 SHEETS-SHEIIT 1.

No. 879,879. I PATENTED FEB. 25, 1908. w. B. KRAFT.

ELECTROMAGNETIC PIANO PLAYER.

APPLICATION FILED JUNE 1 .1 6.

9 90 2 SHEETS-SHEET 2.

i y/hwsse s '45 rectangular box whi WESLEY B. KRAFT, or MILAN, KANSAS.

ELECTROMAGNETIC PIANO-PLAYER.

Specification of Letters Patent.

Patented Feb. 25, 19%.

Application filed June 19' 1906. Serial No. 322.462.

To all whom it may concem:

Be it known that I, WESLEY B: KRA T, a citizen of the United States, residing at Milan, in the county of Sumner and State of Kansas, have invented certain new and useful Improvements in Electromagnetic Piano- Players, of which the following is a specification. v This invention relates to instruments of 19 thatcharacter known as piano players'for .playing pianos, organs, etc., and my object is to produce an instrument in which the operation ofthe musical instrument keys is effected through the alternate energization l5 and deenergization of electro-magnets.

A further object is to produce an instrument of this character'which operates efficientl and reliably, can be easily and quic y'placed in or removed from operative 3p relation to the instrument to be played and which is of simple, strong, durable and inexpensive construction.

With these general objects in view and "others as hereinafter appear the invention -gzz consists.in certain novel and peculiar features bf construction and organization as hereinafter described and claimed; and in order that it may be fully understood reference is to be had to the accompanying drawigure 1, is a top planview of a portion of a piano and a player embodying my invention. Fig. 2, is a vertical section on the line LII-II of Fig. 1. Fig. 3, is a view of a por 3 5 'tion of a perforated note sheet for use with @said player. Fig. 4, is a diagrammatic view ,sho the electric circuitsof theplayer. Fig. 5, 1s a side view, partly broken away, of a'portion of a modified formof the player. 49 6, is an enlar ed dotted line VI of l ig. 2. Fig. 7', is an enlarged detail perspective view of a device for breaking the electric circuits of the player. Y In the said drawingls, 1 indicates an oblong 0 preferably slightly exceeds in length thekey-boa'rd of a piano. 2 "indicates a longitudinal series of electrom ets in said box spaced ,tocorrespond wit the spacing of the white keys of a piano. 3 indicatesa corresponding series of electromagnets in the box spaced to correspondto the spacing-of the black keys and arranged preferably rearward of the white-key magnets.

4 and .5 indicate bloii s secured rigidly upon the front wall of the box and hinged as section taken on the.

at 6 to said blocks are key strikers 7 and 8 respectively, said key strikers being arranged respectively over magnets 2 and 3 and proj ecting rearwardly over and'beyo'nd the rear wall of the box, each key striker being provided at its rear extremity and underside with a cushion 9 and near its hinge point with an armature 10,. to cooperate with its respective electro-magnet, it being noted in this connection that the black-key strikers have their rear portions arched at 11, in order to avoid contact with the white keys of the piano.

12 indicates standards rising from the front of the box by preference and disposed a distance apart slightly exceeding the width of the note sheet hereinafter identified, to be employed in the instrument. Ordinarily the distance between the standards will approxi-' mate fifteen inches, and mounted upon said standards is a casing 13.

14 indicates a horizontalshaft journaled in suitable bearings in the side walls of casing 13 and rigidly secured on said shaft is a feed roller 15 provided with guideflanges 16 at its ends to assist in 'ding the note sheet. 17 indicates a rolfle i' spaced with relation to roller 15 to codperate with the same in feeding the note-sheet through the instrument and grooved or reduced at its ends at 18 by preference to receive the flanges 16 of roller 15.

19 indicates the shaft of roller 17, journaled in bearings 20, arranged for vertical movement in slots 21, in the side walls of the casing 13, springs 22 being secured in said slots and exerting a downward pressure on bearings 20, to cause the roller. 17 to press the note sheet against roller 15.

23 indicates a cross baruconnecting the side walls of the casing forward of roller 15 and preferably curved at its upper side and provided at its ends with upwardly projectin flanges 24 in the vertical lane of the roller flanges 16 to conperate with the latter in preventing lateral movement of the note sheet. 25 indicates a contact bar carried by and preferably at the rear edge of bar 23 and electrically connected by a conductor 26 to one pole of a battery or other source of electric supply 27, the other pole of the battery be' connected by conductors 28 to one terminal of the coils of each. electro-magnet.

29 indicates an insulating bar connecting the side walls of the casing 13, and 30 bars carried by the insulating bar corresponding journaled in the side walls of casing 13. At

' one end the bar is provided with a flattened surface 36, and in the vertical plane of said surface the contiguous wall of the casing 13 is provided with a spring 37. Normally the spring by engagement with the flat side of the rock bar holds the latter as shown in Fig.

2, so as not to interfere with the engagement of the pivoted fingers with contact bar .25

-,when the former are not elevated and insulated from said bar by the note sheet. When it is desired to, break the electric circuit through all of the fingers andthus deenergize all of the magnets, the handle 38 is grasped and turned to rock said rockbar'and cause it to simultaneously elevate all of the fingers 33 and hold them above the plane of the contact bar;

The boX 1 may be supported in any suitable manner, that is may be provided. with supporting legs 39, so that it can be placed up against the front bar 40 of the piano as shown i'nFig. 1 with its key strikers 7 overhanging the white keys 41and its key strikers 8 overhanging the black keys 42 of the piano,

' and to effectually'maintain the player in the relationdescribed, I preferably provide the ends of'the box 1 with eye-bolts 43 to which i are pivotedhooks 44 for enga ement with- 7 eye olts 45 secured in the bloc s 46 at opposite ends of the keyboard of the piano.

After the player is secured as explained,

the desired perforated note sheet 47 is fed rearwardly over bar 23 and contact bar 25 and .between feed rollers 15 and 17. If it is desired to repeat the music, I preferably detachably secure the ends of the note sheet together, the preferred method being to provide the rearend with a transversely alined series of slits 48, andthe other end with a corresponding'series'of tongues 49, to be slipped through the slits 48 and bent back so' as toproject rearwardly at the inner side of the rear end portion of the note sheet. As

thus arranged the tongueswill flatten out as they pass over bar 23, bar 25 and between the .feed rollers, and ofler no resistance to the proper movement of the note sheet, and thus permit the music to be repeated as many times as desired. i

Assuming that the note sheet is in place and the parts otherwise properly assembled,

the rollers are caused to turn in the direction s'raere indicated by the contiguous arrows Fig. 2. They can be turned by hand if desired, but preferably will be turned by means of a spring motor or clockwork as shown in Fig 5. In said figure one end of the shaft 14 is.

provided with a pulley 50 connected by a belt 51 with a pulley 52 journaled on the shaft or spindle of a suitably journaled roller 53 and provided with a gear wheel 54 meshing with a large gear wheel 55 journaled on a shaft 56. Shaft56 is adapted to be j ournaled in the casing and mounted upon and secured to the shaft at its inner end in the usual manner (not shown) is a spring 57 secured at its outer end to a pin 58 rigid Wlilll thecontiguous standard 12.

59 IS a ratchet-rigid on the shaft, and 60 a pivoted pawl carried by wheel 55 and held yieldingly engaged with the ratchet by a spring 61. Bymeans of this spring motor and connections the feed rollers 15 and 17 will operate to effect the travel of the perforated note sheet and as the perforations therein passover the contact bar the respective contact fingers 33 project through said openings and engage said bar and therefore complete an electric circuit, "the result being the magnet attracts its armature and causes the key striker carrying the same to strike and depress the corresponding key of the iano.

' With the arts arranged as described the o eration w'l continue so as to reproduce t 1e same selection as many times as desired,.

it being understood of course that a suitable governor or a clock work escapement, not

shown because of common and well-known construction, will be employed toregulate the speed of the feed rollers. The instrument will also be provided with a dog 62 or its equivalent, to lock the spring against unwinding when not in use.

Where it is desired to employ note sheets of that character in common use which roll and unroll alternately, that is, unwind from one roller and wind upon another and then reverse such movement, I pivot arms 63 carrying a j ournaled roller 64, on the instru ment frame as at 65, and rovide springs 66 to hold said roller presse toward roller 53,

in this instance, being adapted to be detachthe front endof the note sheet numbered 67 ably secured to roller 64 in any suitable manner, the opposite end of the note sheet being permanently mounted upon a roller 68 having its shaft 69 journaled at the lower ends of slots 70 through which the said roller 68 is withdrawn when it is desired to introduce another equipped with a different piece I of music, and to rewind the note sheet from roller 64 onto roller 68 the shaft of the latter is provided with asmall gear wheel 71 meshing with a large gear 72 provided with a crank handle 73. From the above description it will be apevasive parent that I have produced a piano playing mechanism possessing the features of advantage enumerated as desirable and I wish it to be understood that I do not desire to be r strictedto the exact details of construction shown and described as obvious modifications will occur to one skilled in the art.

Having thus described the invention what i I clalm as newanr l desire to secure by Let ters Patent, is

1. A piano player, comprising electro magnets, lever hammers, arinatnres for said magnets carried by said hammers, a perforated note sheet, feed rollers therefor, bar over which the note sheen-travels, pivoted fingers adapted to projectr through the note sheet perforations and engage said bar, a source or electric supply in circuit with said magnets, contact'bar and fingers, means for operating the feed rollers, and an. angular rock bar arranged adjacent toand bearing directly against the contact fingers for moving and holding said fingerslout of contact with 'said contact bar.

2. piano player, comprising electro rnagn'ets, lever hammers, armatures for said" magnets carried by said hammers, a perforated note sheet, feed rollers therefor, a contact bar over which the note sheet travels,

pivoted fingers adapted to project through the note sheet perforations and engage said bar vsource of electric supply in circuit Withsaid magnets, contact-bar and fingers,

means for operating the feed rollers, an an ular rock bar bearing against the contact gers for moving and holding said fingers out of contact with said bar and means for yieldingly holding the rock a contact bar in position to permit the -lingers to engage the contact bar or to hold said lingers out of contact with said bar.

S. In a piano player, the combination of a box arranged to be held to the keyboard of a piano, e'lectro-inagnets Within said box located to corres 70nd to the White and black keys of the piano, blocks of different len ths on the front edge of the said boX, key stri ers hinged to said blocks and having their inner ends adapted to rest on the keys, the inner )ortions of the strikers attached to the longer blocks ,bj'eing arched to clear the 'WllltB keys and engage the black keys, arinatures secured to the under sides of the key strikers,

electrically connected with the electro-magnets.

\ 4. The combination of feed rollers, a convex guide bar adjacent to the feed rollers, a conductor bar secured on the rear edge of the guide bar, contact fingers pivoted above the guide bar and arranged to rest on said con- "ductor bar, a yieldingly-held angularrook bar bearing against the contact fingers, a series of key strikers, and a series of electro-magnets controlling the key strikers and in circuit with the conductor lingers.

' In testimony whereof I ailix my signature, in the presence of two Witnesses.

WESLEY B. KRAFT.

bar and the contact Witnesses:

H. C. RODGERS, G. Y, THORPE.

and, nete sheet controlled circuit closers 

